With rapid development of communications technologies, people exchange information with each other more frequently, and one mobile phone can no longer meet people's requirements. Especially, people who work in sales or management sometimes need two or three or even more mobile phones to meet requirements. However, it is quite inconvenient to carry so many mobile phones. Therefore, a multiple-card multiple-standby mobile phone emerges in the market. With such a mobile phone, a user needs only one mobile phone in which multiple subscriber identity modules may be installed, which is obviously much more convenient than to carry multiple mobile phones.
In the prior art, in a multiple-card multiple-standby single-pass system, multiple mobile phone cards are continually switched between multiple networks of the multiple cards by using one set of communications module (including a radio frequency transceiver module, bottom-layer software, a control chip, and the like), to implement multiple-card multiple-standby in multiple communications modes (communications standards). Because switching occurs very fast, for example, each time of switching takes 1/1000 millisecond, a user cannot perceive that network switching occurs, and it is equivalent to that implementing simultaneous standby networking of multiple cards. In an actual application, if one card is performing a service, the card may be briefly referred to as a service card. The rest cards are in a standby state, and may be briefly referred to as non-service cards. When performing a service, a service card receives and sends communications signaling or data, and to maintain a standby function, a non-service card needs to keep receiving a broadcast message and a paging message. In addition, the non-service card further needs to perform cell measurement when the service card is performing a service. Therefore, a conflict exists between sending and receiving of multiple cards. However, fixed priorities are adopted in a resource allocation method in the prior art. When a conflict exists between resources that different cards apply for, a resource allocation module performs allocation according to a priority of a service. A service with a high priority obtains a resource first, and a service with a low priority obtains a resource later. When services for which application is separately made by two cards have a same priority, allocation is performed according to a sequence of the cards. For example, allocation is performed according to a sequence of a modem 1 and a modem 2. Each time the modem 1 and the modem 2 make application for services simultaneously, a service of the modem 1 may always be allocated, while a service of the modem 2 always cannot be allocated. Consequently, a service conflict cannot be resolved properly, and it is very likely to cause a call drop, a network disconnection or the like because the modem 2 obtains no resource for a long time, and user experience is severely affected.